U.S. patent application number 17/591383 was filed with the patent office on 2022-06-09 for additive manufactured femoral components.
The applicant listed for this patent is Zimmer, Inc.. Invention is credited to Cristina Piecuch.
Application Number | 20220175539 17/591383 |
Document ID | / |
Family ID | 1000006156940 |
Filed Date | 2022-06-09 |
United States Patent
Application |
20220175539 |
Kind Code |
A1 |
Piecuch; Cristina |
June 9, 2022 |
ADDITIVE MANUFACTURED FEMORAL COMPONENTS
Abstract
Described is a femoral component of a prosthetic hip implant.
The femoral component can include: a neck portion; and a stem
portion including a proximal end and a distal end. The neck portion
extends from the proximal end, and the stem portion comprises a
first solid portion and at least one additional portion including
at least one of a hollow portion, a porous portion, and a second
solid portion comprised of a different solid material from a solid
material of the first solid portion. The first solid portion and
the at least one additional portion are in a predetermined
configuration. The femoral component comprises a unitary component
that is formed by additive manufacturing of the femoral component
from a 3D model of the femoral component.
Inventors: |
Piecuch; Cristina; (Winona
Lake, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Zimmer, Inc. |
Warsaw |
IN |
US |
|
|
Family ID: |
1000006156940 |
Appl. No.: |
17/591383 |
Filed: |
February 2, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15846304 |
Dec 19, 2017 |
11259932 |
|
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17591383 |
|
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62457327 |
Feb 10, 2017 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B22F 5/00 20130101; A61F
2002/30962 20130101; B22F 10/20 20210101; A61F 2002/30113 20130101;
A61F 2002/30158 20130101; A61F 2/3662 20130101; B22F 7/004
20130101; A61F 2002/30011 20130101; B33Y 80/00 20141201; A61F
2002/3678 20130101; A61F 2002/30884 20130101; A61F 2/30942
20130101; B33Y 10/00 20141201; B22F 7/06 20130101; A61F 2002/30985
20130101; A61F 2002/3092 20130101; A61F 2002/30014 20130101 |
International
Class: |
A61F 2/36 20060101
A61F002/36; B22F 5/00 20060101 B22F005/00; B22F 7/00 20060101
B22F007/00; B22F 7/06 20060101 B22F007/06; B22F 10/20 20060101
B22F010/20; B33Y 10/00 20060101 B33Y010/00; B33Y 80/00 20060101
B33Y080/00; A61F 2/30 20060101 A61F002/30 |
Claims
1. A femoral component of a prosthetic hip implant, the femoral
component comprising: a neck portion; and a stem portion including
a proximal end and a distal end, wherein the neck portion extends
from the proximal end, and the stem portion comprises at least two
distinct longitudinal stem segments including: a solid segment; and
a hybrid segment including an outer portion defining an outer
surface of the hybrid segment and at least one of a hollow core
portion, a porous core portion, or a solid core portion; wherein
the femoral component comprises a unitary component that is formed
by additive manufacturing of the femoral component from a 3D model
of the femoral component.
2. The femoral component of claim 1, wherein the outer portion of
the hybrid segment is porous.
4. The femoral component of claim 2, wherein the hybrid segment
includes a solid core portion.
5. The femoral component of claim 2, wherein the hybrid segment
includes a porous core portion.
6. The femoral component of claim 2, wherein the hybrid segment
includes at least two of a hollow core portion, a porous core
portion, or a solid core portion.
7-8. (canceled)
9. The femoral component of claim 1, wherein the stem portion is
tapered from the proximal end to the distal end.
10. The femoral component of claim 1, wherein the stem portion has
a cross-sectional profile that is trapezoidal-shaped,
rectangular-shaped, oval-shaped, circular-shaped, or
teardrop-shaped.
11. The femoral component of claim 1, wherein the stem portion
includes a plurality of longitudinally extending flutes along an
outer surface of the solid segment and the outer surface of the
hybrid segment.
12. A prosthetic hip implant comprising: a femoral ball; and a
femoral component comprising: a neck configured to connect to the
femoral ball; and a stem including a proximal end and a distal end,
wherein the neck extends from the proximal end, and the stem
comprises a solid segment and hybrid segment, the hybrid including
at least two of a hollow portion, a porous portion, or a solid
portion; wherein the femoral component comprises a unitary
component that is formed by additive manufacturing of the femoral
component from a 3D model of the femoral component.
13. The prosthetic hip implant of claim 12, further comprising an
acetabular shell.
14-20. (canceled)
21. The prosthetic hip implant of claim 12, wherein the hybrid
segment includes a porous portion, the porous portion defining an
outer surface of the hybrid segment.
22. The prosthetic hip implant of claim 21, wherein the hybrid
segment further includes a solid portion that is circumscribed by
the porous portion.
23. The prosthetic hip implant of claim 22, wherein the hybrid
segment further includes a hollow portion that is circumscribed by
the solid portion.
24. The prosthetic hip implant of claim 22, wherein the hybrid
segment further includes a second porous portion that is
circumscribed by the solid portion.
25. The prosthetic hip implant of claim 21, wherein the hybrid
segment further includes a second porous portion that is
circumscribed by the porous portion.
26. The prosthetic hip implant of claim 25, wherein the hybrid
segment further includes a hollow portion that is circumscribed by
the second porous portion.
27. The prosthetic hip implant of claim 25, wherein the hybrid
segment further includes a solid portion that is circumscribed by
the second porous portion.
28. The prosthetic hip implant of claim 12, wherein the stem is
tapered from the proximal end to the distal end.
29. A femoral component of a prosthetic hip implant, the femoral
component comprising: a solid proximal section including a smooth
outer surface; a solid distal section including a smooth outer
surface; and a hybrid middle section disposed between the proximal
section and the distal section, the middle section including a
circumferential porous portion defining an outer surface of the
middle section, an inner cavity defined by an inner circumferential
wall of the circumferential porous portion, and an I-beam-shaped
solid segment disposed within the inner cavity, wherein the
circumferential porous portion is permeated with interconnected
interstitial pores structured to promote at least one of bone
ongrowth or bone ingrowth; wherein the femoral component comprises
a unitary component that is formed by additive manufacturing from a
3D model of the femoral component.
Description
CLAIM OF PRIORITY
[0001] This patent application is a continuation of U.S. patent
application Ser. No. 15/846,304, filed on Dec. 19, 2017, which
claims the benefit of priority, under 35 U.S.C. Section 119(e), to
Cristina Piecuch, U.S. patent application Ser. No. 62/457,327,
entitled "ADDITIVE MANUFACTURED FEMORAL COMPONENT," filed on Feb.
10, 2017, each of which is hereby incorporated by reference herein
in its entirety.
TECHNICAL FIELD
[0002] The present subject matter relates generally to orthopedic
implants and methods of manufacturing an orthopedic implant. In
particular, the present disclosure relates to a femoral component
of a hip implant that is manufactured by an additive manufacturing
process.
BACKGROUND
[0003] Artificial implants, including hip joints, shoulder joints,
and knee joints, are widely used in orthopedic surgery. Artificial
hip and shoulder joints are generally ball and socket joints,
designed to match as closely as possible the function of the
natural joint. To duplicate a joint's natural action, a total joint
replacement implant has three parts: a stem component, which fits
into the femur or humerus and provides stability; a ball component,
which replaces the spherical head of the femur or humerus; and a
cup component, which replaces the worn-out hip or shoulder
socket.
[0004] There are many types of stern components that can be used in
joint replacement surgery to secure the artificial ball that will
articulate with the artificial socket or cup. Some stem components
are modular, allowing a greater range of options during the
surgery. Each component comes in various sizes in order to
accommodate various body sizes and types. In some designs, the stem
and ball are one piece; in other designs, they may be provided as
separate pieces. In further designs, the stern and ball components
can feature a modular body, a removable neck, or any combination of
these or additional features. Such designs and their combinations
will be referred to throughout this document as "modular," and are
intended to allow for additional customization and fit.
[0005] Specifically, modular stem components may be provided in any
number of lengths and widths. Corresponding modular bodies, necks
and balls can be provided in various sizes, allowing the surgeon to
select the best options for a particular patient. Other stem
components may be non-modular, and may provide a stem, neck, and
ball in a one-piece configuration.
OVERVIEW
[0006] In the realm of orthopedic surgery, it is known to use
implants to fix the position of bones. In this way, bones can be
reconstructed, and malformations or other injuries corrected.
However, different bones within the body have different functions
and are exposed to different forces and stresses. Consequently, a
single type of orthopedic implant is not well suited for implanting
into the various types of bones which experience different forces
and stresses, nor into different patients that may have different
needs.
[0007] Orthopedic implant design is complicated by large bending
stiffness (or flexural rigidity) of the implant, which is at least
10 times greater than cortical bone. Effects of a stiffness
mismatch between the implant and bone have been extensively studied
relating to total hip arthroplasty (THA). Clinical experience has
shown that the stiffness mismatch is a primary cause of accelerated
bone resorption due to stress shielding. This response to
sub-optimal bone loading can lead to loss of proximal support,
implant subsidence, potential bone fracture, possible fatigue
fracture of the implant, and, most importantly, reduction of bone
stock that jeopardizes the outcome of any future revision
surgery.
[0008] The present inventor has recognized the need for orthopedic
implants that can have physical properties that are varied and are
capable of addressing differing types of forces and stresses on the
implants. Particularly, a need to individualize such an implant for
each particular patient is recognized by the inventor.
[0009] Additive manufacturing is a name used to describe
technologies that build three-dimensional (3D) objects by adding
layer-upon-layer of material. The material can be a plastic, a
metal, concrete, etc. It is common to use 3D modeling software
(Computer Aided Design or CAD) in order to provide a sketch or
plan, which is followed by a machine or other equipment that lays
down successive layers of material to fabricate a 3D object.
[0010] The present inventor has recognized, among other things,
that additive manufacturing can be used to fabricate orthopedic
implants, and particularly specialized or custom orthopedic
implants that address certain anatomies or issues, such as stress
shielding. A benefit of using such additive manufacturing of
orthopedic implants is that the entire implant can be made using a
single unit operation fabrication for manufacturing complete parts
of various configurations having both a solid portion and a porous
and/or hollow portion. Also, the location and configuration of the
porous (or hollow) and solid portions can be customized to address
certain anatomies and to address stress shielding while maintaining
fatigue performance of the device, for example. Another benefit of
the manufacturing process is that there are reduced manufacturing
costs compared to specialized and conventional manufacturing
methods. The lower costs result from lower set up costs and
economies of scale associated with additive manufacturing one-off
components. A further benefit is that custom implants can be
designed based on the anatomy and desired joint articulation of
specific patients, which would not be possible with conventional
manufacturing processes.
[0011] This overview is intended to provide an overview of subject
matter of the present patent application. It is not intended to
provide an exclusive or exhaustive explanation of the present
subject matter. The detailed description is included to provide
further information about the present patent application.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] In the drawings, which are not necessarily drawn to scale,
like numerals may describe similar components in different views.
Like numerals having different letter suffixes may represent
different instances of similar components. The drawings illustrate
generally, by way of example, but not by way of limitation, various
embodiments discussed in the present document.
[0013] FIG. 1 shows a side view of a femoral component and other
components of a hip joint endoprosthesis in accordance with at
least one example of the present disclosure;
[0014] FIG. 1A shows a cross-section through the femoral component
of FIG. 1 along line 1A-1A in accordance with at least one example
of the present disclosure;
[0015] FIG. 1B shows another cross-section through the femoral
component of FIG. 1 along line 1A-1A in accordance with at least
one example of the present disclosure;
[0016] FIG. IC shows another cross-section through the femoral
component of FIG. 1 along line 1A-1A in accordance with at least
one example of the present disclosure;
[0017] FIG. 2 shows a side view of a femoral component of a hip
joint endoprosthesis in accordance with at least one example of the
present disclosure;
[0018] FIG. 2A shows a cross-section through the femoral component
of FIG. 2 along line 2A-2A in accordance with at least one example
of the present disclosure;
[0019] FIG. 2B shows another cross-section through the femoral
component of FIG. 2 along line 2A-2A in accordance with at least
one example of the present disclosure;
[0020] FIG. 3 shows a side view of a femoral component of a hip
joint endoprosthesis in accordance with at least one example of the
present disclosure;
[0021] FIG. 3A shows a cross-section through the femoral component
of FIG. 3 along line 3A-3A in accordance with at least one example
of the present disclosure; and
[0022] FIG. 3B shows another cross-section through the femoral
component of FIG. 3 along line 3A-3A in accordance with at least
one example of the present disclosure.
DETAILED DESCRIPTION
[0023] With reference to the human body and components of the
system described herein which are intended to be implanted in the
human body, the terms "proximal" and "distal" are defined in
reference to the location at which a limb is connected to the
torso, with the term "proximal" being the end of the limb, bone or
plate closer to the torso, and the term "distal" being the end of
the limb, bone or plate further from the torso. In addition, the
term "lower" and "upper" in reference to plate surfaces are
designations in which the lower surface is that surface closer to
or seating on the bone and the upper surface is that surface
opposite the lower surface.
[0024] The present disclosure relates to an orthopedic implant. In
particular, the present disclosure relates to a prosthetic hip
implant, including a femoral component comprising: a neck portion;
and a stem portion including a proximal end and a distal end,
wherein the neck portion extends from the proximal end, and the
stem portion comprises at least one solid portion and at least one
hollow or porous portion in a predetermined configuration; wherein
the femoral component is formed by additive manufacturing of the
femoral component from a 3D model of the femoral component based
upon an intended implantation position of the femoral component in
a bone of a patient. The femoral component can be manufactured by
additive manufacturing of the entire part, inclusive of its solid
and porous (or hollow) portions.
[0025] Any additive manufacturing process can be used to make the
implant, including direct metal laser sintering (DMLS), selective
laser sintering, and electron beam melting, for example.
[0026] Referring to FIG. 1, a hip implant 10 is shown according to
an example of the present disclosure. Implant 10, including all of
its components, can be constructed of a biocompatible material such
as titanium, titanium alloy, cobalt chrome, stainless steel,
magnesium, niobium, tantalum, etc., and composites thereof, or
other metals, polymers or alloys suitable for a hip prosthesis.
Implant 10 can comprise three primary components, which can include
an acetabular component 40, a femoral ball 50, and a femoral
component 100. The femoral component 100 can fit in or attach to
the femoral ball 50. The femoral ball 50 can then rest inside
recess 42 of acetabular component 40, which can be implanted into a
hip of a patient. Femoral ball 50 can rotate within recess 42 of
the acetabular component 40. Femoral ball 50 can be
spherically-shaped, as shown, or, alternatively, can have other
suitable shapes, which can include flattened portions. The
acetabular component 40 can be a monoblock or can be modular. The
femoral ball 50 in this disclosure is not limited to the specific
example shown in FIG. 1, and can encompass all suitable femoral
ball designs known in the art. Similarly, the acetabular component
is not limited to the specific example shown in FIG. 1 but can
include all suitable acetabular component designs known in the
art.
[0027] The femoral component 100 can be formed as a unitary body or
component, or alternatively can be formed as a multi-part component
with the multiple parts assembled together. Regardless of whether
the femoral component 100 is formed as a unitary body/component or
a multi-part component, it can be divided into at least three
portions for description purposes that can vary in purpose,
composition and shape, for example. A first section can be a neck
section 110 that is a proximal-most portion of the femoral
component 100 and that can function to connect the femoral
component 100 to the femoral ball 50. The neck section 110 can have
a proximal end 112 that can have a short cylindrical configuration
and can have a slight taper. This proximal end 112 can be
configured to be received in a correspondingly shaped and sized
cylindrical recess 52 in the femoral ball 50. Together, proximal
end 112 and recess 52 can form a Morse taper connection, for
example.
[0028] A second section of the femoral component 100 can be a
middle section 120. The middle section 120 can have an elongated
tapering shape that extends distally between the neck section 110
and a distal section 130, which is a third section of the femoral
component 100. Alternatively, however, the middle section may not
be tapered and could have a more uniform width. The middle section
120 can have a trapezoidal-shaped cross-section, although other
shapes are also contemplated.
[0029] Other styles, shapes and configurations of the femoral
component are contemplated, besides those shown and described
herein. For example, the femoral component can also be one of the
following: an uncemented tapered wedge component (e.g., having a
blade, a trapezoidal or a square cross-section) with a proximal
porous coating on only proximal macro features for fixation (e.g.,
having no porous coating, but one that can be possibly grit
blasted); an uncemented fit and fill component (e.g., having a
tapered round cross-section with porous coating on proximal 2/3 of
component, a tapered round cross-section with splines and no porous
coating, a fully cylindrical cross-section with porous coating
along its full or partial length, or a fully cylindrical
cross-section with no porous coating); and a cemented component
(e.g., having an oval cross-section or rectangular cross-section,
which is typically tapered along its length). The examples of
femoral components shown and described in the present disclosure
are examples, and any other suitable types of femoral components
are also contemplated.
[0030] In particular, the femoral component 100 in FIG. 1 is
considered to be a blade style of femoral implant. It is
contemplated that the use of the hip implant 10 and style of the
hip implant 10 can vary depending upon a particular patient and a
particular surgical location in the patient's body. Although the
orthopedic implants shown and described herein are generally those
that can be used in hip replacement or revision surgeries, other
anatomical uses for the subject matter of this disclosure are
contemplated, such as for use in implant systems for the lower leg
or upper arm, for example.
[0031] The neck and distal sections 110, 130 of the femoral
component 100 can have solid cross-sections. The middle section
120, however, can have a cross-section that includes both solid,
porous and/or hollow components. Solid components of the middle
section 120 can be included to withstand fatigue loading in vivo.
Internal porous and/or hollow components of the middle section 120
can be included. to reduce flexural rigidity and the weight of the
stem 100. Porous outer surface features can be included to induce
bone ingrowth. The combination of both solid, porous and/or hollow
components can allow the stem 100 to be optimized for flexure
stiffness to more closely match that of bone and also to minimize
stress shielding.
[0032] Transitions between the sections 110, 120 and 130 of the
stem 100 can be optimally included and located in order to avoid
high stress zones in the implant and to meet industry standards.
The femoral component 100 can be made using additive manufacturing
techniques to have a continuous, integrated structure, including
any of the three cross-sections 140, 150 and 160, such as those
shown and described herein. However, other suitable cross-sections
including solid portions and porous and/or hollow portions are also
contemplated.
[0033] FIGS. 1A, 1B and 1C depict examples of three different
cross-sections 140, 150, and 160, respectively, of the middle
section 120 of femoral component 100 taken at 1A-1A in FIG. 1. The
middle section 120 in all three cross-sections 140, 150 and 160 can
have a cross-section having a trapezoidal-shaped profile, as shown.
However, other shapes of an outer perimeter or surface of the
cross-section are also contemplated by the disclosure, such as, for
example, oval-shaped, rectangular-shaped, circular-shaped, or
teardrop-shaped. Other suitable shapes are also contemplated,
however. The middle section 120 can also include, as shown, a
porous outer layer 126 to induce bone ingrowth and/or ongrowth.
[0034] A first exemplary cross-section 140 of the middle section
120 of femoral component 100 in FIG. 1, shown in FIG. 1A, can
include a core (or longitudinal chamber or aperture) 142 that is
porous. By "porous," it is meant that the material is permeated
with interconnected interstitial pores. The porous structure can be
formed by additive manufacturing using suitable materials, metals
or metal alloys known in the art. Alternatively, however, the core
142 can be hollow, or, in other words, the core 142 can be
considered to be an aperture. The cross-section 140 can also
include a first circumferential solid portion 144 adjacent the core
142. In another example, the core 142 can be formed from a solid
material that is different from the solid material of the solid
portion 144, which may have a different mechanical property. For
example, the mechanical property of strength of the core 142, if it
were a solid portion can be less than that of the solid portion
144. Other examples of mechanical properties that can differ in the
second solid portion of the core 142 from the solid portion 144
include, but are not limited to, yield strength, compressive
strength, fatigue strength, impact strength, deformation, strain,
deflection, elasticity, and plasticity, etc.
[0035] Further, the cross-section 140 can include a second
circumferential porous portion 146 adjacent the first
circumferential solid portion 142, and which can serve as an outer
surface of the middle section 120. The second circumferential
porous portion 146 can be formed by additive manufacturing at the
same time as the additive manufacturing of the stem 100, or can be
independently manufactured and bonded to the stem 100 by one of the
following processes: titanium or titanium alloy plasma spray,
sintering of metal beads or metal wire mesh on the stem 100 or
diffusion bonding or resistance bonding of trabecular metal pads
onto the stem 100 (the additive manufactured porous section 146 and
the trabecular metal pads are configured to replace the porous
structure of natural bone itself). Thus, the second circumferential
porous portion (or outer layer) 146 can promote bone ongrowth
and/or ingrowth pending the design of the layer or portion.
[0036] The porous structure of the second circumferential porous
portion 146, and any other porous portions described herein, can be
adapted for the ongrowth and/or ingrowth of cancellous and cortical
bone spicules, for example. In an exemplary embodiment, the size
and shape of the porous structure can emulate the size and shape of
the porous structure of natural bone. Preferably, the average pore
diameter of the porous portions described herein, particularly
those porous portions that comprise an outer surface of one of the
femoral components described herein, can be about 40 .mu.m to about
800 .mu.m with a porosity from about 45% to about 65%. Further, the
interconnections between pores can have a diameter larger than
about 50-60 microns. In short, the geometric configuration of the
porous structure can be configured to encourage natural bone to
migrate and grow into the porous structure.
[0037] Although specific ranges are given for pore diameters,
porosity, and interconnection diameters, these ranges are exemplary
and are applicable to one example. In other examples, these ranges
could be modified, and the resulting femoral component can still be
within the scope of this disclosure.
[0038] A second exemplary cross-section 150 of the middle section
120 of femoral component 100, shown in FIG. 1B, can include a solid
portion 154 that can include two longitudinal chambers or apertures
(if hollow) 152 that are located side-by-side. The two longitudinal
chambers 152 can be porous, hollow, or, alternatively, formed of a
different solid material (having a different strength, for example)
from the solid portion 154. The solid portion 154 can be surrounded
by a circumferential porous portion 156 that can make up the outer
surface of the middle section 120 of femoral component 100.
[0039] A third exemplary cross-section 160 of the middle section
120 of femoral component 100, shown in FIG. 1C, can include a solid
portion 164 having generally an I-beam-shape. The I-beam-shaped
solid portion 164 can have two flange portions 168 that are
connected by a web portion 169. As shown, the two flange portions
168 can be curved to fit the shape of the outer surface or
perimeter of middle section 120 as shown, although other shapes are
contemplated. Voids can be created in the cross-section 160 by the
placement of the I-beam-shaped solid portion 164, which can form
two longitudinal chambers or apertures 162. The two longitudinal
chambers 162 can be porous, as described herein with regard to the
porous core 142 of FIG. 1A, or can be hollow. Alternatively, the
chambers can instead be formed from another solid material that
differs from the solid material forming the solid portion 164,
formed from a metal or polymer for example, which can have a
different strength, for example. A porous portion 166 can surround
the I-beam shaped solid portion 164 and the two longitudinal
chambers 162 (whether porous, hollow or a solid), and can comprise
the outer surface of the middle section 120.
[0040] FIG. 2 shows a side view of another example of a femoral
component 200 in accordance with the present disclosure. In
particular, the femoral component 200 in FIG. 2 is considered to be
a cylindrical-stemmed implant. The femoral component 200 can be
formed as a unitary body or component, or alternatively can be
formed as a multi-part component with the multiple parts assembled
together. Regardless of whether the femoral component 200 is formed
as a unitary body/component or a multi-part component, it can be
divided into at least three portions for description purposes that
can vary in purpose, composition and shape, for example. A first
section can be a neck section 210 that is a proximal-most section
of the femoral component 200 and that can function to connect, the
femoral component 200 to a femoral ball (not shown). The neck
section 210 can have a proximal end 212 that can have a short
cylindrical configuration and can have a slight, taper. This
proximal end 212 can be configured to be received in a
correspondingly shaped and sized cylindrical recess in a femoral
ball (not shown).
[0041] A second section of the femoral component 200 can be a
middle section 220. The middle section 220 can have an elongated
cylindrical tapering shape that extends distally between the neck
section 210 and a distal section 230, which is a third section, of
the femoral component 200.
[0042] The neck and distal sections 210, 230 of the femoral
component 200 can have solid cross-sections. The middle section
120, however, can have a cross-section that includes both solid and
porous (or hollow) components. Solid components of the middle
section 220 can be included to withstand fatigue loading in vivo.
The porous or hollow components of the middle section 220 can be
included to reduce flexural rigidity and the weight of the stem
200, as well as to induce bone ingrowth, if the outer surface is
porous. The combination of both solid and porous (or hollow)
components can allow the stem 200 to be optimized for flexure
stiffness to more closely match that of bone and also to minimize
stress shielding.
[0043] Transitions between the sections 210, 220 and 230 of the
stem 200 can be optimally included and located in order to avoid
high stress zones in the implant and to meet industry standards.
The femoral component 200 can be made using additive manufacturing
techniques to have a continuous, integrated structure, including,
for example, either of the two cross-sections 240 and 250, such as
those shown and described herein. Other suitable cross-sections are
also contemplated, however.
[0044] FIGS. 2A and 2B include two different exemplary
cross-sections 240 and 250, respectively, of the middle section 220
of femoral component 200 taken at 2A-2A in FIG. 2, for example. The
middle section 220 in both cross-sections 240 and 250 can have a
cross-section having a circular-shaped profile, as shown. However,
other shapes of an outer perimeter or surface of the cross-section
are also contemplated by the disclosure. The middle section 220
also includes, as shown, a porous outer layer 226.
[0045] The first exemplary cross-section 240 of the middle section
220 of femoral component 200 in FIG. 2, shown in FIG. 2A, can
include a core (or longitudinal chamber) 242 that is porous. The
porous structure can be formed by additive manufacturing at the
same time as the solid internal geometry 244 or 254. Alternatively,
however, the core 242 can be hollow (in other words, can be an
aperture) or can be made of a solid material that is different
(such as having a different strength) from a solid material used in
another portion of the middle section 220. The cross-section 240
can include a first circumferential solid portion 244 adjacent the
core 242.
[0046] In another example, the core 242 can be formed from a solid
material that is different from the solid material of the solid
portion 144, which can have a different mechanical property. For
example, the mechanical property of strength of the core 242, if it
were a solid portion can be less than that of the solid portion
244.
[0047] Other examples of mechanical properties that can differ in
the second solid portion of the core 242 from the solid portion 244
include, but are not limited to, yield strength, compressive
strength, fatigue strength, impact strength, deformation, strain,
deflection, elasticity, and plasticity, etc.
[0048] Further, the cross-section 240 can include a second
circumferential porous portion 246 adjacent the first
circumferential solid portion 242, and which serves as an outer
surface of the middle section 220. The second circumferential
porous portion 246 can be formed by additive manufacturing at the
same time as the solid sections 244, or can be independently
manufactured and bonded to the stem 200 by one of the following
processes: titanium or titanium alloy plasma spray, sintering of
metal beads or metal wire mesh onto the stem 200 or diffusion
bonding or resistance bonding of trabecular metal pads onto the
stem 200 (the additive manufactured porous section 246 and
trabecular metal pads are configured to replicate the porous
structure of natural bone itself). Thus, the second circumferential
porous portion (or outer layer) 246 can promote bone ongrowth
and/or ingrowth pending the design of the layer.
[0049] The second exemplary cross-section 250 of the middle section
220 of femoral component 200, shown in FIG. 2B, can include a solid
portion 254 that includes two longitudinal chambers or apertures
252 that are located side-by-side. The two longitudinal chambers
252 can be porous or, alternatively, can be hollow (or, in other
words, can be apertures) or made of a solid material that differs
from another solid portion (such as 254) of middle section 220. The
solid portion 254 can be surrounded by a circumferential porous
portion 256 that can make up the outer surface of the middle
portion 220 of femoral component 200.
[0050] FIG. 3 shows a side view of another example of a femoral
component 300 in accordance with the present disclosure. In
particular, the femoral component 300 in FIG. 3 is considered to
have a cylindrical tapered, fluted stem. The femoral component 300
can be formed as a unitary body or component, or alternatively can
be formed as a multi-part component with the multiple parts
assembled together. Regardless of whether the femoral component 300
is formed as a unitary body/component or a multi-part component, it
can be divided into at least two portions for description purposes
that can vary in purpose, composition and shape, for example. A
first section can be a neck section 310 that is a proximal-most
portion of the femoral component 300 and that can function to
connect the femoral component 300 to a femoral ball (not shown).
The neck section 310 can have a proximal end 312 that can have a
short cylindrical configuration and can have a slight taper. This
proximal end 312 can be configured to be received in a
correspondingly shaped and sized cylindrical recess in a femoral
ball (not shown).
[0051] A second section of the femoral component 200 can be a stem
section 320. The stem section 220 can have an elongated tapering
shape that extends distally from the neck section of the femoral
component 300. The stem section 320 can include a plurality of
longitudinally extending flutes 328 along an incremental length of
the outer surface thereof Sharp edges on the flutes 328 can dig
into a cortical bone wall of an intramedullary canal in a bone, for
example, and can increase torsional stability of the stem section
320 during use of the prosthesis in a patient's body. The
cross-sectional geometry, the number and the length of the flutes
328 included in the stem section 320 can be adjusted to facilitate
resistance to torsional loadings on the hip prosthesis.
[0052] The neck section 310 of the femoral component 300 can have a
solid cross-section. The stem section 320, however, can have a
cross-section that includes both solid and porous components. Solid
components of the stem section 320 can be included to withstand
fatigue loading in vivo. The porous components of the stem section
320 can be included to reduce flexural rigidity and the weight of
the femoral component 300, as well as to induce bone ingrowth, if
the outer surface is porous. The combination of both solid and
porous components allows the femoral component 300 to be optimized
for flexure stiffness to more closely match that of bone and also
to minimize stress shielding.
[0053] Transitions between the sections 310 and 330 of the femoral
component 300 can be optimally included and located in order to
avoid high stress zones in the implant and to meet industry
standards. The femoral component 300 can be made using additive
manufacturing techniques to have a continuous, integrated
structure, including either of the two cross-sections 340 and 350,
such as those shown and described herein.
[0054] FIGS. 3A and 3B include two different exemplary
cross-sections 340 and 350, respectively, of the stem section 320
of femoral component 300 taken at 3A-3A in FIG. 3, for example. The
stem section 320 in both cross-sections 340 and 350 can have a
cross-section having a circular profile, as shown. However, other
shapes of an outer perimeter or surface of the cross-section are
also contemplated by the disclosure. The stem section 320 can also
include a plurality of longitudinally extending flutes 328 which
project outwardly from an outer surface of the stem section
320.
[0055] The first exemplary cross-section 340 of the stern section
320 of femoral component 300, shown in FIG. 3A, can include a core
(or longitudinal chamber or aperture) 342 that is porous. The
porous structure can be formed of a metal alloy using additive
manufacturing. Alternatively, however, the core 342 can be hollow
or of solid construction of an alternative material including but
not limited to metal, metal alloy or polymers. The cross-section
340 can include a first circumferential solid portion 344 adjacent
the core 342. The core 342, alternatively, can be made of a solid
material that is different from the solid portion 344. The solid
portion 344 can include a plurality of longitudinally extending
flutes 328 as shown.
[0056] In another example, the core 342 can be formed from a solid
material that is different from the solid material of the solid
portion 444, which can have a different mechanical property. For
example, the mechanical property of strength of the core 342, if it
were a solid portion can be less than that of the solid portion
344. Other examples of mechanical properties that can differ in the
second solid portion of the core 342 from the solid portion 344
include, but are not limited to, yield strength, compressive
strength, fatigue strength, impact strength, deformation, strain,
deflection, elasticity, and plasticity, etc.
[0057] The second exemplary cross-section 350 of the stem section
320 of femoral component 300, shown in FIG. 3B, can include a solid
portion 354 that includes two longitudinal chambers or apertures
352 that are located side-by-side. The two longitudinal chambers
352 can be porous or, alternatively, can be solid and made of an
alternative material, or can be hollow. The solid portion 354 can
include a plurality of longitudinally extending flutes 328 as
shown. The stem section 320 of femoral component 300 can,
alternatively, include a solid distal section that does not include
a porous portion.
[0058] Prior to hip replacement or revision surgery, a surgeon can
use x-ray technology to template, or determine the type and size of
implant (or its components) that the surgeon will use,
Alternatively, or additionally, during a hip replacement or
revision, for example, a surgeon can take a number of measurements
to ensure proper prosthesis selection, limb length and hip
rotation. After making an incision, the surgeon can gain access to
the joint and push the femur out of the socket, thereby exposing
the joint cavity. A deteriorated femoral head can be removed and
the acetabulum can be prepared by cleaning and enlarging with
circular reamers of gradually increasing size. Also, the surgeon
may measure the native femoral head once it is excised to determine
the size and type of implant to use. In addition, after the joint
is dislocated, and as the surgeon is preparing the bone (possibly
removing bone) for the implant, the surgeon can determine the
size/offset of the implant to be implanted by using trials (or
provisional implants) in the joint that represent the implants that
are available. The trial or provisional implants are used to check
tissue tension, joint stability, range of motion and leg length. A
new acetabular shell, which can be metal, can be implanted securely
within the prepared hemispherical socket. A plastic inner can be
placed within the metal acetabular shell and fixed into place. If
the old acetabular shell is sufficient, during a revision surgery,
the shell may not be replaced, and only a new liner may be
used.
[0059] Next, the femur can be prepared to receive a stem of a
femoral component. The inside of the femur can include a
intramedullary canal that can be cleaned and enlarged by broaches,
reamers, and other tools, thereby creating a cavity that is smaller
than, but that corresponds to the outer profile of the implant
stem. That outer profile or geometry is dictated by the size and
shape of the stern and should be prepared so that the stem, upon
insertion, can fit tightly and securely in the canal. The stern can
be placed in the canal with or without cement. Finally, a femoral
ball can be attached to a proximal end of the stem and can be
seated within a cup so the joint is properly aligned. The incision
can then be closed.
[0060] The present disclosure includes a method of manufacturing a
femoral component of a prosthetic hip implant, the method
comprising: creating a 3D model of the femoral component; and
additive manufacturing of the femoral component from the 3D model,
wherein the femoral component comprises: a neck portion; and a stem
portion that comprises a first solid portion and at least one
additional portion including at least one of a hollow portion, a
porous portion, and a second solid portion comprised of a different
solid material from a solid material of the first solid portion,
wherein the first solid portion and the at least one additional
portion are in a predetermined configuration. The step of additive
manufacturing can, for example, include direct metal laser
sintering the femoral component, selective laser sintering the
femoral component or electron beam melting the femoral
component.
[0061] The present disclosure also contemplates use of software to
additively manufacture (e.g., 3D print) the femoral component
described herein. Thus, the present disclosure contemplates a
system comprising: a display that displays a printing template,
wherein the printing template describes a femoral component
comprising: a neck portion; and a stem portion including a proximal
end and a distal end, wherein the neck portion extends from the
proximal end, and the stem portion comprises a first solid portion
and at least one additional portion, the at least one additional
portion including at least one of a hollow portion, a porous
portion, or a second solid portion comprised of a different solid
material from a solid material of the first solid portion, wherein
the first solid portion and the at least one additional portion are
in a predetermined configuration; and a module that, in response to
a printing template by a user, executes the printing template to
generate a geometric representation for use as input to a 3D
printer.
[0062] Additionally, the present disclosure also contemplates a
method comprising: displaying a printing template, wherein the
minting template describes a femoral component comprising: a neck
portion; and a stem portion including a proximal end and a distal
end, wherein the neck portion extends from the proximal end, and
the stem portion comprises a first solid portion and at least one
additional portion, the at least one additional portion including
at least one of a hollow portion, a porous portion, or a second
solid portion comprised of a different solid material from a solid
material of the first solid portion, wherein the first solid
portion and the at least one additional portion are in a
predetermined configuration; and executing the printing template to
generate a geometric representation for use as input to a 3D
printer.
[0063] Changes and modifications, additions and deletions may be
made to the structures and methods recited above and shown in the
drawings without departing from the scope or spirit of the
disclosure and the following claims.
VARIOUS NOTES & EXAMPLES
[0064] To further illustrate the femoral component of the hip
implant, and the methods disclosed herein, the following
non-limiting examples are provided:
[0065] Example 1 includes a femoral component of a prosthetic hip
implant, the femoral component comprising: a neck portion; and a
stem portion including a proximal end and a distal end, wherein the
neck portion extends from the proximal end, and the stem portion
comprises a first solid portion and at least one additional
portion, the at least one additional portion including at least one
of a hollow portion, a porous portion, or a second solid portion
comprised of a different solid material from a solid material of
the first solid portion, wherein the first solid portion and the at
least one additional portion are in a predetermined configuration;
wherein the femoral component comprises a unitary component that is
formed by additive manufacturing of the femoral component from a 3D
model of the femoral component.
[0066] Example 2 includes the femoral component of example 1,
wherein the at least one additional portion includes a hollow core
extending longitudinally through at least a portion of the stem
portion and a porous portion circumscribing the first solid
portion, and wherein the first solid portion circumscribes the
hollow core.
[0067] Example 3 includes the femoral component of example 1,
wherein the at least one additional portion includes a porous core
extending longitudinally through at least a portion of the stem
portion and a second porous portion circumscribing the first solid
portion, and wherein the first solid portion circumscribes the
porous core.
[0068] Example 4 includes the femoral component of any one of
examples 1-3, wherein the neck portion is solid and at least a
portion of the stem portion located. at or near the distal end is
solid.
[0069] Example 5 includes the femoral component of example 1,
wherein the at least one additional portion includes a first
aperture and a second aperture that extend longitudinally through
at least a portion of the stern portion, wherein the first solid
portion surrounds the first and second apertures, and wherein the
at least one additional portion further includes a first porous
portion circumscribing the first solid portion.
[0070] Example 6 includes the femoral component of example 1,
wherein the at least one additional portion includes a first porous
portion and a second porous portion that extend longitudinally
through at least a portion of the stem portion, wherein the first
solid portion surrounds the first and second porous portions, and
wherein the at least one additional portion further includes a
third porous portion circumscribing the first solid portion.
[0071] Example 7 includes the femoral component of example 1,
wherein the first solid portion comprises an I-beam-shaped solid
portion extending longitudinally through at least a portion of the
stem portion, wherein the at least one additional portion includes
a first porous portion circumscribing the I-beam-shaped solid
portion and forming an outer surface of at least a portion of the
stem portion, and wherein the at least one additional portion
further includes a first aperture and a second aperture that extend
longitudinally through at least a portion of the stem portion
between the I-beam-shaped solid portion and the first porous
portion.
[0072] Example 8 includes the femoral component of example 1,
wherein the first solid portion comprises an I-beam-shaped solid
portion extending longitudinally through at least a portion of the
stem portion, wherein the at least one additional portion includes
a first porous portion circumscribing the I-beam-shaped solid
portion and forming an outer surface of at least a portion of the
stern portion, and wherein the at least one additional portion
further includes a second porous portion and a third porous portion
that extend longitudinally through at least a portion of the stem
portion between the I-beam-shaped solid portion and the first
porous portion.
[0073] Example 9 includes the femoral component of any one of
examples 1-8, wherein the stem portion is tapered from the proximal
end to the distal end.
[0074] Example 10 includes the femoral component of any one of
examples 1-9, wherein the stem portion has a cross-sectional
profile that is trapezoidal-shaped, rectangular-shaped,
oval-shaped, circular-shaped, or teardrop-shaped.
[0075] Example 11 includes the femoral component of any one of
examples 1-10, wherein the stem portion includes a plurality of
longitudinally extending flutes along a length of an outer surface
thereof.
[0076] Example 12 includes a prosthetic hip implant comprising: a
femoral ball; and a femoral component comprising: a neck portion
configured to connect to the femoral ball; and a stem portion
including a proximal end and a distal end, wherein the neck portion
extends from the proximal end, and the stem portion comprises a
first solid portion and at least one additional portion including
at least one of a hollow portion, a porous portion, and a second
solid portion comprised of a different solid material from a solid
material of the first solid portion, wherein the first solid
portion and the at least one additional portion are in a
predetermined configuration; wherein the femoral component
comprises a unitary component that is formed by additive
manufacturing of the femoral component from a 3D model of the
femoral component.
[0077] Example 13 includes the prosthetic hip implant of example
12, further comprising an acetabular shell.
[0078] Example 14 includes a method of manufacturing a femoral
component of a prosthetic hip implant, the method comprising:
creating a 3D model of the femoral component; and additive
manufacturing of the femoral component from the 3D model, wherein
the femoral component comprises a unitary component comprising: a
neck portion; and a stem portion including a proximal end and a
distal end, wherein the neck portion extends from the proximal end,
and the stem portion comprises a first solid portion and at least
one additional portion including at least one of a hollow portion,
a porous portion, and a second solid portion comprised of a
different solid material from a solid material of the first solid
portion, wherein the first solid portion and the at least one
additional portion are in a predetermined configuration.
[0079] Example 15 includes the method of example 14, wherein the
step of additive manufacturing includes direct metal laser
sintering the femoral component, selective laser sintering the
femoral component or electron beam melting the femoral
component.
[0080] Example 16 includes the method of example 14, wherein the at
least one additional portion includes a hollow core extending
longitudinally through at least a portion of the stem portion and a
porous portion circumscribing the first solid portion, and wherein
the first solid portion circumscribes the hollow core.
[0081] Example 17 includes the method of example 14, wherein the at
least one additional portion includes a porous core extending
longitudinally through at least a portion of the stem portion and a
second porous portion circumscribing the first solid portion, and
wherein the first solid portion circumscribes the porous core.
[0082] Example 18 includes the method of any one of examples 14-17,
wherein the neck portion is solid and at least a portion of the
stem portion located at or near the distal end is solid.
[0083] Example 19 includes the method of example 14, wherein the at
least one additional portion includes a first aperture and a second
aperture that extend longitudinally through at least a portion of
the stem portion, wherein the first solid portion surrounds the
first and second apertures, and wherein the at least one additional
portion further includes a first porous portion circumscribing the
first solid portion.
[0084] Example 20 includes the method of example 14, wherein the at
least one additional portion includes a first porous portion and a
second porous portion that extend longitudinally through at least a
portion of the stem portion, wherein the first solid portion
surrounds the first and second porous portions, and wherein the at
least one additional portion further includes a third porous
portion circumscribing the first solid portion.
[0085] Each of these non-limiting examples can stand on its own, or
can be combined in any permutation or combination with any one or
more of the other examples.
[0086] The above detailed description includes references to the
accompanying drawings, which form a part of the detailed
description. The drawings show, by way of illustration, specific
embodiments in which the present subject matter can be practiced.
These embodiments are also referred to herein as "examples." Such
examples can include elements in addition to those shown or
described.
[0087] However, the present inventors also contemplate examples in
which only those elements shown or described are provided.
Moreover, the present inventors also contemplate examples using any
combination or permutation of those elements shown or described (or
one or more aspects thereof), either with respect to a particular
example (or one or more aspects thereof), or with respect to other
examples (or one or more aspects thereof) shown or described
herein.
[0088] In the event of inconsistent usages between this document
and any documents so incorporated by reference, the usage in this
document controls.
[0089] In this document, the terms "a" or "an" are used, as is
common in patent documents, to include one or more than one,
independent of any other instances or usages of "at least one" or
"one or more." In this document, the term "or" is used to refer to
a nonexclusive or, such that "A or B" includes "A but not B," "B
but not A," and "A and B," unless otherwise indicated. In this
document, the terms "including" and "in which" are used as the
plain-English equivalents of the respective terms "comprising" and
"wherein." Also, in the following claims, the terms "including" and
"comprising" are open-ended, that is, a system, device, article,
composition, formulation, or process that includes elements in
addition to those listed after such a term in a claim are still
deemed to fall within the scope of that claim. Moreover, in the
following claims, the terms "first," "second," and "third," etc.
are used merely as labels, and are not intended to impose numerical
requirements on their objects.
[0090] The above description is intended to be illustrative, and
not restrictive. For example, the above-described examples (or one
or more aspects thereof) may be used in combination with each
other. Other embodiments can be used, such as by one of ordinary
skill in the art upon reviewing the above description. The Abstract
is provided to comply with 37 C.F.R. .sctn. 1.72(b), to allow the
reader to quickly ascertain the nature of the technical disclosure.
It is submitted with the understanding that it will not be used to
interpret or limit the scope or meaning of the claims. Also, in the
above Detailed Description, various features may be grouped
together to streamline the disclosure. This should not be
interpreted as intending that an unclaimed disclosed feature is
essential to any claim. Rather, inventive subject matter may lie in
less than all features of a particular disclosed embodiment. Thus,
the following claims are hereby incorporated into the Detailed
Description as examples or embodiments, with each claim standing on
its own as a separate embodiment, and it is contemplated that such
embodiments can be combined with each other in various combinations
or permutations. The scope of the present subject matter should be
determined with reference to the appended claims, along with the
full scope of equivalents to which such claims are entitled.
* * * * *